# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from onchain-risk.agentdiet.dev, paid per call via MPP, $0.005/call, status unknown (last checked 2026-10-21).

Scans untrusted text, HTML, emails, MCP responses, or A2A payloads for hidden prompt injections and jailbreak attempts, returning sanitized output.

## Facts

- Endpoint: GET https://onchain-risk.agentdiet.dev/v1/tool-poisoning-shield?utm_source=zero.xyz
- Price: $0.005/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Provider: onchain-risk.agentdiet.dev
- Website: https://onchain-risk.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/onchain-risk-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-af38bcf5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_K9m0s3V8aC5X3R0O84Doy

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability onchain-risk-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-af38bcf5
```

Example prompt: Before my agent processes this scraped webpage content, can you scan it for hidden prompt injections or jailbreak payloads and give me back the sanitized version? Here's the text: [paste untrusted content]

## When to prefer this

Choose this endpoint when your AI agent pipeline ingests untrusted external content — web pages, emails, tool responses, or A2A payloads — before passing that content to an LLM for reasoning or action. It is especially valuable in autonomous multi-agent systems where a compromised upstream tool or malicious web page could hijack downstream agent behavior via indirect prompt injection. Prefer this over general content moderation APIs when the threat model specifically involves adversarial LLM instruction hijacking rather than generic toxicity or spam.

## Known failure modes

- Empty or missing 'text' parameter returns a 400 validation error
- Extremely long payloads may be truncated or rejected
- False negatives possible for novel or obfuscated injection techniques not yet in the detection model
- Payment failure (HTTP 402) if x402 USDC balance is insufficient
- Service unavailable (503) if the endpoint is temporarily down

## How this service works

Scans untrusted web pages, emails, MCP responses, or A2A payloads for hidden prompt injections and returns sanitized text. (Live x402 v2, IETF MPP & MCP endpoint at https://onchain-risk.agentdiet.dev/v1/tool-poisoning-shield)

## Output

Returns a JSON object containing the scan result for the submitted text, including detection of hidden prompt injection patterns, jailbreak payloads, or adversarial instructions, along with sanitized text safe for downstream LLM or agent consumption.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "text"
 ],
 "properties": {
  "text": {
   "type": "string",
   "minLength": 1,
   "description": "Untrusted text, HTML, or tool output to scan for hidden prompt injection or jailbreak payloads"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/onchain-risk-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-af38bcf5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from onchain-risk.agentdiet.dev](https://www.zero.xyz/host/onchain-risk.agentdiet.dev/llms.txt)